Really depends on your scale. If you just run half a rack of equipment a lot of these costs are factored in by your housing company. But you come to a certain point where you need to invest in a RIPE membership, where you need a router that costs 100k€. Plus a spare one. Where you need someone to watch the monitoring 24h sitting in the DC - just in case. Even if a lot of this stuff is free, it needs to be setup up and managed all the time.
Let alone the cost for DDoS mitigation. Thats an easy 300k€ worth of equipment plus lets say 2x40 GBit/s links for lets say 40k€ each per link and month. Over the course of two years thats easy 1 million euros, just to handle DDoS. Even if you just need 10 GBit/s capacity, you might need 10x that capacity in a DDoS situtation.
Here's the reason no one thinks about those things: no one makes their numbers public.
Or at least I've never stumbled across a blog post with anything like a line item cost range for everything that goes into DC or cloud networking.
And in the absence of transparency, yeah, people are going to assume they're getting screwed.
(I understand why this is. The networking free market seems to do a decent job at fulfilling needs, but it turns all those things into secret sauce that shouldn't be shared.)
Let alone the cost for DDoS mitigation. Thats an easy 300k€ worth of equipment plus lets say 2x40 GBit/s links for lets say 40k€ each per link and month. Over the course of two years thats easy 1 million euros, just to handle DDoS. Even if you just need 10 GBit/s capacity, you might need 10x that capacity in a DDoS situtation.